Method and apparatus for managing random access procedure for short data transmission based on discard timer in wireless communication system

A user equipment (UE) in a wireless communication system, the UE comprising:

• at least one transceiver;
• at least one processor;
• and
• at least one computer memory operably connectable to the at least one processor and storing instructions that, when executed, cause the at least one processor to perform operations comprising:
• upon a reception of a Packet Data Convergence Protocol (PDCP) service data unit (SDU) from an upper layer, starting a discard timer related to the PDCP SDU;
• generating a medium access control (MAC) protocol data unit (PDU) including the PDCP SDU;
• starting a random access (RA) procedure for transmitting the MAC PDU in a radio resource control (RRC) INACTIVE state;
• and
• based on the discard timer expiring before the RA procedure is completed, stopping the RA procedure.

An apparatus for a user equipment (UE), the apparatus comprising:

• at least one processor;
• and
• at least one computer memory operably connectable to the at least one processor and storing instructions that, when executed, cause the at least one processor to perform operations comprising:
• upon a reception of a Packet Data Convergence Protocol (PDCP) service data unit (SDU) from an upper layer, starting a discard timer related to the PDCP SDU;
• generating a medium access control (MAC) protocol data unit (PDU) including the PDCP SDU;
• starting a random access (RA) procedure for transmitting the MAC PDU in a radio resource control (RRC) INACTIVE state;
• and
• based on the discard timer expiring before the RA procedure is completed, stopping the RA procedure.

A computer readable storage medium storing at least one computer program comprising instructions that, when executed by at least one processor, cause the at least one processor to perform operations for a user equipment (UE), the operations comprising:

• upon a reception of a Packet Data Convergence Protocol (PDCP) service data unit (SDU) from an upper layer, starting a discard timer related to the PDCP SDU;
• generating a medium access control (MAC) protocol data unit (PDU) including the PDCP SDU;
• starting a random access (RA) procedure for transmitting the MAC PDU in a radio resource control (RRC) INACTIVE state;
• and
• based on the discard timer expiring before the RA procedure is completed, stopping the RA procedure.